双向受弯钢筋混凝土梁受剪承载力计算

Calculation of the shear capacity of reinforced concrete beams under biaxial bending

分析双向受弯梁混凝土受压区类型、面积大小和中性轴倾角变化规律。基于合理的假定,推导出双向受弯梁受剪承载力计算的等效单向受弯截面计算公式,并根据受力方向的不同,对箍筋作用和截面承载力进行等效。在有关文献的单向受弯梁受剪承载力计算方法的基础上,分别提出有腹筋和无腹筋双向受弯简支梁在集中荷载作用下的受剪承载力计算公式。通过对相关文献中的32个试验梁实测数据的计算显示,该方法的计算值与试验值吻合良好。通过现行规范算法的计算检验,表明该法计算简便,可供工程设计参考。

Based on an analysis of the variation patterns of concrete compressive zone, compression area and neutral axis angle of the cross section of reinforced concrete beams under biaxial bending, three basic hypotheses are proposed. A method for deriving the equivalent single bending cross-section dimensions for a biaxial flexural member is developed. The stirrup action and shear bearing capacity of the cross-section are projected to the direction of the external load. On the base of the formulas for calculating the shear strength of reinforced concrete beams under simple bending in the literature, the shear capacity calculation methods are established for biaxial flexural simple supported beam with or without stirrups under concentrated loads. The calculation results of 32 specimens described in the literature using the proposed methods are in good agreement with the experimental ones. Calculations using the shear capacity formulas under single bending in the current code for design of concrete structures show that the proposed method is convenient and suitable in design.